diff --git a/app/src/main/java/eu/faircode/email/DaoAttachment.java b/app/src/main/java/eu/faircode/email/DaoAttachment.java
index 5a1a8a453a..5d24c741bc 100644
--- a/app/src/main/java/eu/faircode/email/DaoAttachment.java
+++ b/app/src/main/java/eu/faircode/email/DaoAttachment.java
@@ -108,6 +108,12 @@ public interface DaoAttachment {
             " AND NOT (error IS :error)")
     void setWarning(long id, String error);
 
+    @Query("UPDATE attachment" +
+            " SET name = :name, type = :type, size= :size" +
+            " WHERE id = :id" +
+            " AND NOT (name IS name AND type IS :type AND size IS :size)")
+    void setName(long id, String name, String type, Long size);
+
     @Query("UPDATE attachment" +
             " SET type = :type" +
             " WHERE id = :id" +
diff --git a/app/src/main/java/eu/faircode/email/EntityAttachment.java b/app/src/main/java/eu/faircode/email/EntityAttachment.java
index a32f3db19b..396771fec0 100644
--- a/app/src/main/java/eu/faircode/email/EntityAttachment.java
+++ b/app/src/main/java/eu/faircode/email/EntityAttachment.java
@@ -32,12 +32,19 @@ import androidx.room.ForeignKey;
 import androidx.room.Index;
 import androidx.room.PrimaryKey;
 
+import java.io.BufferedInputStream;
+import java.io.BufferedOutputStream;
 import java.io.File;
+import java.io.FileInputStream;
+import java.io.FileOutputStream;
 import java.io.IOException;
+import java.io.InputStream;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Locale;
 import java.util.Objects;
+import java.util.zip.ZipEntry;
+import java.util.zip.ZipOutputStream;
 
 import javax.mail.Part;
 
@@ -335,6 +342,23 @@ public class EntityAttachment {
         return type;
     }
 
+    void zip(Context context) throws IOException {
+        File file = getFile(context);
+        File zip = new File(file.getAbsolutePath() + ".zip");
+
+        try (InputStream in = new BufferedInputStream(new FileInputStream(file))) {
+            try (ZipOutputStream out = new ZipOutputStream(new BufferedOutputStream(new FileOutputStream(zip)))) {
+                ZipEntry entry = new ZipEntry(name);
+                out.putNextEntry(entry);
+                Helper.copy(in, out);
+            }
+        }
+
+        DB db = DB.getInstance(context);
+        db.attachment().setName(id, name + ".zip", "application/zip", zip.length());
+        file.delete();
+    }
+
     public static boolean equals(List<EntityAttachment> a1, List<EntityAttachment> a2) {
         if (a1 == null || a2 == null)
             return false;